The rise of blockchain technologies has triggered tremendous research interest, coding efforts, and monetary investments in the last decade. Ethereum is the single largest programmable blockchain platform today. It features cryptocurrency trading, digital art, and decentralized finance through smart contracts. So-called Ethereum nodes operate the blockchain, relying on a vast supply chain of third-party software dependencies maintained by diverse organizations. These software suppliers have a direct impact on the reliability and the security of Ethereum. In this article, we perform an analysis of the software supply chain of Java Ethereum nodes and distill the challenges of maintaining and securing this blockchain technology.